In the present study the nutritionally important components were determined, with the conventional nutrients analyses, in 53 kinds of cultivated or wild edible mushrooms species, from various Macedonian areas. Macedonian mushrooms contained relatively high total protein content (10.6-51.2%, dry mass) and were low in fats (1.2-14.0%, dry mass). 100 g dry mushrooms comprised low energetic value of 1650.0 kJ on the average. The contents of minerals showed great variation (4.3-17.9%, dry mass) in agreement with literature data.

Prevention of chronic diseases and particularly heart diseases stimulated the interest in many countries for developing designed foods with less animal products and more new items in the diet (7). Such are the edible mushrooms which are classified as food of the future because the protein content in most species is higher than in most other not animal foods. They contain low fats, their cultivation takes a short time and it is inexpensive. Except for some cultivated mushrooms, little is known about the nutritional quality of the wild-spread, edible mushrooms species from Macedonia. Their great number (about 120) enables selecting of those which are characterized with great nutritional quality. In order to improve the mushroom quality, it is desirable to investigate their chemical content as well as to study the nutritional quality in details.

Samples

The nutritionally important components were determined in 53 kinds of edible mushrooms species from various Macedonian areas. 5 samples were cultured mushrooms samples from manufactures and different private producers in Macedonia. 47 wild mushroom samples were obtained from the repurchased stations or collected in different Macedonian areas in the period between 1997-99 year. All the samples were determined and quoted in the Macedonian collection of mushrooms, which belongs to the Institute of Biology at the Faculty of Natural Sciences in Skopje. After collecting, dry matter content was determined immediately by drying at 105°C and the remaining part was stabilized, dried and milled to pass a 0.2 mm screen. All the samples represent the whole mushroom and for determination was analyzed in triplicate.

Methods

The nutritionally important components were determined with the conventional nutrients analyses. The levels of total nitrogen were determined by the Kjeldahl method (960.52, AOAC), and percent protein was calculated as % N x 6.25. Fats content was determined by the Soxhlet method (920.39, AOAC). By dry ashing of the mushroom samples at 400°C, ash content was gravimetricaly investigated (920.08, AOAC). The energy values given in kJ were calculated by multiplication with the corresponding factors and subsequent summation of the determined amounts of the energy supplying main constituents i.e. protein, fats and available carbohydrates. The factors were taken from the European Commission Directions on the identification of food products nutritional values (1).

Table 1 presents dry matter, total nitrogen, total protein, fats and ash content data of the mushroom samples used in this study, expressed as a percentage on a dry mass basis. Mean values, were calculated where there was more than one sample from the same species but with different origin. Dry matter content in the investigated Macedonian mushrooms is relatively low if compared to other foods (10). The results coincide reasonably well with those for Yugoslavian mushrooms (6,8). The average dry matter value of 10.5 % is comparable with the theoretical value of 10 % dry matter content in mushrooms, which was always used in the literature data, where this investigations is not done. The great part of dry matter content from the investigated mushrooms consists of their proteins (30.7%) and ash contents (9.6%). Calvatia caelata and Macrolepiota mastoidea contained the highest levels of total protein whereas Laetiporus sulphureus and Cantharellus cibarius had the lowest. Correlation coefficient between dry matter and total protein content was not significant with p<0.05 level of probability (r=0.04;t=0.41). Thus, a higher dry matter content in the mushrooms could not be attributed to their protein content. Our obtained values for total proteins are close to those reported in the literature: for Agaricus bisporus by Braaksma from Netherlands and Surinrut from Norway, for Pleurotus ostreatus by Vetter (12) in Hungary and for Cantharellus cibarius reported by Miljković in Yugoslavija, Surinrut in Norway and Danell in Sewerage. Higher levels were obtained in our Lentinus edodes and Boletus edulis mushrooms than in those from Thailand (11) and Yugoslavia (6). Macedonian mushrooms showed great variation in the mineral content level depending on the species and place of growing, as it is also stated in the literature data (13). Fats in the investigated samples were present in low quantities. The correlation of dry matter and fats content values was not significant with p<0.05 level of probability (r=0.05; t=0.53). Our values for fats in Cantharellus cibarius are similar to those reported by Džamić in the same mushrooms from Yugoslavia, whereas in Boletus edulis they were lower. Other fats values in Macedonian mushrooms agree reasonably well with the levels in more Italian species, reported by Cavazzoni.

Macedonian mushrooms contain great total proteins and minerals, have low contents of fats and represent a low energetic and nutritionally valuable source of food.

1. Amtsblatt der Europäischen Gemeinschaft Nr. L 276/40 of 6.10.1990.

2. AOAC Official Methods of Analysis, 16th ed., AOAC International,Arlington 1995.

3. Braaksma A., Schaap D.J. (1996): Protein analysis of the common mushroom Agaricus bisporus. Postharvest Biology and Technology. 7, 119-27.

4. Cavazzoni V., Adami A., Aragozzini F., Craveri R. (1987): Fatty acid composition of mycelial biomasses of some mushrooms. Lebensm.-Wiss. Technol. 20, 133-6

5. Danell E., Eaker D. (1992): Amino acids and total protein content of the edible mushroom Cantharellus cibarius. J Sci Food Agric. 60, 333-337.

6. Džamić M., Mijković B., Zorić D.(1985): Dry matter, carbohydrates and lipids in some edible mushrooms in the Toplica province. Agrohemija. 2, 143-58.

7. FAO/WHO Protein quality evaluation. (1991): Food and agricultural organization of the United Nations, Rome.

8. Miletić I, Stanimirović D, Stanimirović D. (1984): Quantity, composition and nutritional value of protein in some edible wild mushrooms. Hrana i ishrana. 24, 159-169.

9. Miljković B., Džamić M. (1984): Study of proteins and amino acids in mushroom species Boletus edulis and Cantharellus cibarius. Arh. Poljopr. Nauke. 45, 479-90.

10. Souci S.W., Fachmann W., Kraut H.(1994): Food Composition and Nutrition Tables, Meddpharm-Scientific Publishers, Stuttgart.

11. Surinrut P., Julshamn K., Njaa L. (1987): Protein, amino acids and some major and trace elements in Thai and Norwegian mushrooms. Qual.Plant.-Plant Foods Hum. Nutr. 2, 117-25.

12. Vetter J., Imre R.(1993): Crude, digestible and non-digestible proteins in fruit bodies of Pleurotus ostreatus. Z.Lebensm.-Unters.Forsch. 197, 427-8.

13. Vetter J. (1993): Chemical composition of eight edible mushrooms. Z.Lebensm.-Unters.Forsch. 196, 224-7.